Apple is busy developing and testing new iOS 5 for iPhone, iPad and iPod touch and has so far released 4 beta versions for developers to test/debug. Recently iOS 5 Beta 4 has been released for the developers however the Jailbreak community was too fast in releasing the Jailbreak for it. Its easy to jailbreak it using redsn0w 0.9.8b4 as per procedure already explained here.

Strange thing for Apple fans is that Jailbreak devices wont be able to upgrade to iOS 5 Beta 4 using OTA method means Apple does not want you to Jailbreak your devices. This was confirmed by MuscleNerd of iPhone Dev-Team in his tweet below,

The 5.0b4 OTA update won’t work on JB devices due to an explicit check of /Applications..almost like a present from Apple

NOTE:It appears that by design, the OTA update that became available starting with iOS 5 beta4 will *not* be automatically applied to jailbroken devices. That’s a relief to those who don’t want to lose their jailbreak via OTA pushes. If you’re jailbroken, you’ll need to use the standard iTunes method to get to iOS 5 beta4.

Right now the Redsnow Jailbreak provided is tethered which means after reboot the device has to be jailbroken again using Redsnow “boot tethered” option however we could expect an untethered jailbreak after release of final public iOS 5.

The major change in iOS 5 Beta 4 is Wifi Sync which allows you to Sync with you PC or Mac via iTunes using Wifi i.e. without cable. Other major features of iOS 5 betas include Notification Center, iMessage (like Blackberry Messenger), Newsstand, Reminders, Twitter integration, Photo Editing and Safari upgrades.

iOS 5 Betas are currently available for apple developers only. To become one of them you have to pay 99$ per year and you can download all Betas alongwith documentations and tools. You can apply for developer account from apple developer page here.